module.exports = (totalSize,req,res)=>{
  const range =req.headers['range']
  if(!range){
    return{code:200}
  }
  const sizes =range.match(/bytes=(\d*)-(\d*)/)
  const end = sizes[2] || totalSize-1
  const start = size[1] || totalSize-end

  if(start>end || start<0 || end>totalSize){
    return{code:200}
  }
  res.setHeader('Accept-Ranges','bytes')
  res.setHeader('Content-Range',`bytes ${start}-${end}-${totalSize}`)
  res.setHeader('Content-Length',end-start)
  return{
    code:206,
    start:parseInt(start),
    end:parseInt(end)
  }
}